Unfortunately, the scientists haven't trained the mice use their ultrasonic songs to replicate the Queen of the Night aria or anything, but rather have shown that they possess the brain matter capable of learning.

Previously, the prevailing assumption was that the ultrasonic songs that male mice use in courtship were innate, and that the rodents were not capable of adjusting their sounds through social cues. The researchers found that male mice housed together would gradually learn to match pitch with each other. They also discovered that when the mice sing, their motor cortex region is active and projects directly to brainstem vocal motor neurons — a level of complexity never before guessed.

This is an extremely basic level of vocal learning, nowhere near what some other creatures are capable of. The researchers also haven't found signs of any other sort of song change, such as syntax or frequency modulation. They've proposed a continuum of vocal learning, "with vocal mimics and some supposed vocal non-learning species at either extreme." That would put mice somewhere between animals that can't learn to change their sounds, and those that can: parrots, hummingbirds, songbirds, humans, whales, dolphins, sea lions, bats and elephants.